Metal systems have a lot of advantages over most roof systems. But there's a lot of manufacturers that specify various detail procedures to meet their warranty criteria; some wouldn't recommend any felts but another type of underlayment. For some, stapping is OK. Personally, I wouldn't install metal over even one layer of shingles and I think you'd have a problem with most AHJ's trying to go over two.
Painted steel roofing
Any big fans out here? Everyone seems to want prices on steel. THe pricing is not a problem if I know how I want it put down. Been lucky enough to talk myself out of the steel until now. Have 3 roofs to price out and am quite sure that someone will stick me with the steel
Did a few steel roofs with another contractor a few years ago..didn't care for doing them myself, but work is work. He had the roof stripped and layered 30# felt and went right over the roof boards (no plywood). Always wondered how the condensation thing would work out with all that dead air space in the attic....All the time knowing damn well that holes are being punched in the felt from previous nails.
Talked to the guy that handles the roofing at the local supplier and he says, lay OSB, felt and then the steel. Little to no airspace between steel and the roof deck means that there should be little to no condensation.
I believe my competition plans on laying down pearlins and laying the steel right over the whole roof. I would have to say a no no since it already has 2 layers of shingles on it so I won't be going that way.:laughing: I have seen this done before on roofs any takes on the pros and cons.
Did a few steel roofs with another contractor a few years ago..didn't care for doing them myself, but work is work. He had the roof stripped and layered 30# felt and went right over the roof boards (no plywood). Always wondered how the condensation thing would work out with all that dead air space in the attic....All the time knowing damn well that holes are being punched in the felt from previous nails.
Talked to the guy that handles the roofing at the local supplier and he says, lay OSB, felt and then the steel. Little to no airspace between steel and the roof deck means that there should be little to no condensation.
I believe my competition plans on laying down pearlins and laying the steel right over the whole roof. I would have to say a no no since it already has 2 layers of shingles on it so I won't be going that way.:laughing: I have seen this done before on roofs any takes on the pros and cons.
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I would never go over 2 layers..... with anything.:no: HO made a reference to what someone else maybe pricing it out to do. Told him at that point that I would be pricing it to take it down to the deck.Metal systems have a lot of advantages over most roof systems. But there's a lot of manufacturers that specify various detail procedures to meet their warranty criteria; some wouldn't recommend any felts but another type of underlayment. For some, stapping is OK. Personally, I wouldn't install metal over even one layer of shingles and I think you'd have a problem with most AHJ's trying to go over two.
Last fall I worked on an existing steel roof - layed right on the roof boards, no felt, nothing. You could see the bright galvanized underside through the cracks between the roof boards from inside the attic. Had been there 25 years and had another 25 years in it. It had started leaking because 25 years ago they put it down with nails with lead grommets and they had started pulling up. Replaced thousands - I think the count was 2,500 nails - one by one with new roofing screws. Not a drip thereafter. Great roofs.
I see no problem going over 2 layers of ashalt shingles So long as your using long enuff woodbinders to go thru the decking. yes id rather have clear deck but with dump fees being what they are and customers having tighter wallets you do what you can.
I grew up on the farm and can remember many barns with tin roofs and dont recal cond problems, my shop now dosnt have insulation yet and i dont see it either
I grew up on the farm and can remember many barns with tin roofs and dont recal cond problems, my shop now dosnt have insulation yet and i dont see it either
2 or 3 yrs ago, I went over a 2 layer asphalt roof with a 26 gauge Kynar 500 finished steel standing seam roof.
Underlayment, 1x4's screwed into the decking 2 ft. O.C., Panel width was about 11 inches. Roof pitch was 4/12
Came out pretty well.
In the city of Naperville, IL they will allow a 3rd layer of metal with a letter from a Structual Engineer or Architect saying the structual members can handle the extra weight.
Couple of weeks ago I talked to the chief building inspector about it.
( the job I mentioned was not in Naperville )
Underlayment, 1x4's screwed into the decking 2 ft. O.C., Panel width was about 11 inches. Roof pitch was 4/12
Came out pretty well.
In the city of Naperville, IL they will allow a 3rd layer of metal with a letter from a Structual Engineer or Architect saying the structual members can handle the extra weight.
Couple of weeks ago I talked to the chief building inspector about it.
( the job I mentioned was not in Naperville )
My other home was built in 1902 with a tin roof. That lasted until 1988 at which time was replaced with Galv steel roof and screws. No sheating on the roof, no felt or any kind of underlayment. Just steel on wood and it has never leaked nor shows any signs of rusting on either side. The home does have a full uninsulated attic, 30'X60' with 7' ceiling.
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